Abstract: This optical disk device includes a pickup, an offset means, a focus servo means, and a layer jump means. The offset means generates a focus error signal on the basis of the output of the pickup, and applies an offset voltage to that focus error signal. And the layer jump means performs layer jump operation, including kick start operation, kick end operation taking a second threshold value as a reference, brake start operation taking a third threshold value as a reference, and brake end operation. Moreover, before executing this layer jump operation, the layer jump means changes this second threshold value or this third threshold value, according to the value of the offset voltage.

Abstract: In an optical disk apparatus, an optical pickup includes an actuator for driving an object lens, and a sensed signal output part for making it possible to generate a tracking error signal and a lens error signal by addition/subtraction, and a signal processor includes a servo signal generator for generating a tracking error signal and a lens error signal on the basis of a signal supplied from the sensed signal output part, and a tracking offset correction quantity signal generator supplied with the lens error signal to output a tracking offset correction quantity signal. DC (direct current) offset correction is conducted by conducting addition/subtraction between the tracking error signal and both the lens error signal and the tracking offset correction quantity signal.

Abstract: A differential phase detector for an optical storage system is set forth. The differential phase detector includes a photodetector circuit arranged to detect light deviations associated with radial errors in the optical storage system. A non-linear equalizer is in communication with the photodetector circuit. The output of the non-linear equalizer is in communication with signal processing circuitry. The signal processing circuitry uses the equalized signals to generate one or more radial error signals.

Abstract: An apparatus for recording and reproducing an information signal on and from an optical disc includes a memory. The information signal is written into the memory. The information signal is read out from the memory. An optical head generates a laser beam in response to the readout information signal, and applies the laser beam to the optical disc to record the readout information signal on the optical disc. A test signal is recorded on a position of the optical disc near a recording position thereof via the optical head during the writing of the information signal into the memory. The test signal is reproduced from the optical disc. The reproduced test signal is evaluated to generate an evaluation result. An intensity of the laser beam is optimized in response to the evaluation result.

Abstract: An information recording and/or reproducing apparatus includes an optical head, an analog signal processor, an analog/digital converter, a controller and a digital/analog converter. The optical head is used for emitting a light beam on a medium and receiving a reflected light beam from the medium. The analog signal processor is used for processing the reflected light beam to obtain a first analog signal. The analog/digital converter is used for converting the first analog signal into a digital signal. The controller is used for applying a low-pass filtering operation on the digital signal to obtain a digital controlling signal. The digital/analog converter is used for converting the digital controlling signal into a second analog signal. The second analog signal is transmitted to the optical head for correcting a tilt between the light beam and the medium.

Abstract: In an interlayer movement apparatus for moving the focal point of the laser light to an arbitrary layer, there are provided an objective lens which collects the laser light from an optical source, a focus actuator which makes the objective lens move in its optical axis direction, a focus error detection means for detecting the convergent state of the laser light on the information layer of the optical disc, and an interlayer movement control system for making the focal point of the laser light move to an information layer two or more layers apart by controlling the focus actuator according to a relative speed between the information layer of the optical disc and the focal point which was calculated using the time required for the focal point of the laser light passing through the respective layers which was measured on the basis of the output signal of the focus error detection means and the respective interlayer distances which are specified by the optical disc specifications.

Abstract: The invention provides an apparatus for controlling servo signal gains of an optical disc drive. The apparatus adjusts the gains of a plurality of servo signals controlling a servo system of the optical disc drive when the optical disk drive encounters an operating state transition. In a first mode, at least one AGC loop of the apparatus compensates the gains of the servo signals with a selectable bandwidth during a specific period after the operating state transition to accelerate the convergence of the servo signals. In a second mode, at least one AGC loop of the apparatus reloads the previously saved convergence values or pre-determined values as the initial values according to the current operating state immediately after the operating state transition to accelerate the convergence of the servo signals.

Abstract: An optical drive includes: an optical pickup; a preprocessing circuit which processes an optical signal detected by the optical pickup; nonvolatile memory having stored therein relation information which represents the relation of a signal balance with respect to a signal difference between a TE signal and an FE signal at the time of a predetermined operation of the optical pickup; and a central processing circuit which performs focus control of the optical pickup. The preprocessing circuit generates the signal balance of the optical pickup. The preprocessing circuit also obtains the FE signal and the TE signal with respect to the optical disc. The central processing circuit derives a phase difference and an amplitude difference from the signal balance and the relation information, and calculates, based on the differences and the TE signal, a FE signal suitable for the predetermined operation.

Abstract: An optical disc drive according to the present invention can write data on both a write-once disc and a rewritable disc. The drive includes: a disc recognizing section 110 for recognizing the type of a given optical disc as a write-once disc or a rewritable disc; and track skipping detection signal generating section, which outputs track skipping detection signal when a first condition on tracking error is satisfied if the given optical disc, on which data is being written, has turned out to be a write-once disc. On the other hand, if the given optical disc has turned out to be a rewritable disc, the track skipping detection signal generating section outputs track skipping detection signal when a second condition on tracking error, which is different from the first condition, is satisfied. A control section stops writing the data in response to the track skipping detection signal while the data is being written.

Abstract: A position control apparatus (optical apparatus) is disclosed which is capable of preventing disadvantages caused by the absence of a dead band while achieving a required accuracy of positional control. The position control apparatus comprises a controller which controls the drive of an object (optical member) so that the position of the object, which detected by a position detector, moves closer to a target position. The controller has a control function which does not drive the object in a case where the difference between the position detected by the position detector and the target position is within a predetermined range, and changes the predetermined range according to control modes relating to the drive of the object.

Abstract: Disclosed herein are aspects of optical tape technology, tape manufacturing, and tape usage. Methods and systems of tape technology disclose optical tape media including: configurations, formulations, markings, and structure; optical tape manufacturing methods, systems, and apparatus methods and systems including: curing processes, coating methods, embossing, drums, testing, tracking alignment stamper strip; optical tape methods and systems including: pick up head adapted for the disclosed optical tape; and optical tape uses including optical storage media devices for multimedia applications.

Abstract: Provided is a drive signal generating apparatus including: an arithmetic section that calculates an approximate expression to approximate variations of multiple detected values each representing one of a position of an optical pickup section and an amount of positional deviation of the optical pickup section with respect to a current target position, the position of the optical pickup section being sequentially detected when the optical pickup section moves stepwise toward multiple target positions set in advance on a drawing surface of a drawing target; and a drive signal generation section that generates a second drive signal synchronized with a first drive signal for causing the optical pickup section to move stepwise, the second drive signal having a signal value corresponding to an approximate value calculated by substituting a value associated with each of the multiple target positions into the approximate expression so as to move an optical component provided in the optical pickup section.

Abstract: A method for generating an RFZC signal is provided. The method includes the following steps. First, an RF signal is received and the received RF signal is converted into an RF-ENVLP signal. Next, a DC offset of the RF signal is calibrated according to a variation of the RF-ENVLP signal so as to obtain a calibrated RF-ENVLP signal and obtain a gain according to the calibrated RF-ENVLP signal. Then, an RFZC signal is generated according to the calibrated RF-ENVLP signal and the gain.

Abstract: A tracking system for an optical drive includes a focus error module. The focus error module generates a focus error signal based on a difference between a first sensor output signal and a second sensor output signal, which are based on a reflected portion of a laser beam that is reflected by an optical storage medium. A control module generates a tracking signal based on the focus error signal.

Abstract: A reading method and a reading device for an optical disk drive, which reads data on a track of an optical disk, receives a host command to read required data, checks cache data, reads cache required data to respond to the command, sets the required data to a target track of the optical disk if no required data exists, calculates moving time for which an optical head is moved from a current position to the target track by way of track jumping and track skipping, respectively, compares the moving time for the track skipping and the track jumping with each other, selects one of the track jumping and the track skipping corresponding to the shorter one of the moving time, moves the optical head to the target track to read the required data and responds to the host command to enhance the reading efficiency.

Abstract: An optical disk device executes a seek operation to move an irradiation position of light beam on an optical disk to a track of a target address. During execution of a seek operation through a one-track jump operation in which the irradiation position of the light beam is moved along the radial direction of the optical disk by one track, it is determined whether or not off-track of the irradiation position of the light beam has occurred. When it is determined that the off-track has occurred, a seek operation through a multiple track jump operation is executed in which the irradiation position of the light beam is moved along the radial direction of the optical disk by an amount corresponding to a plurality of tracks.

Abstract: A method and a device for fast disc recognition for use in read/write performances when an optical disc is connected to an optical drive, including the provision of a set S of parameters for safe data transfer between the drive and the disc, the direct calibration during a disc recognition step only of those parameters out of said set S in need of a direct calibration, the start of a read/write data transfer sequence after said disc recognition step is finalized and the calibration of the remaining parameters at first after or during one or more data transfer read/write sequences.

Abstract: An optical disc device and tracking control method capable of stable tracking control even for inferior optical discs with tracks decentered by a large amount. The optical disc device and tracking control method includes: obtaining a rotation angle at which the degree of displacement of the track due to the eccentricity of the optical disc becomes maximum on the inner circumference side and the outer circumference side, and detecting the eccentricity amount of the optical disc; and performing track pull-in at the rotation angle, at which the degree of displacement of the track due to the eccentricity of the optical disc becomes maximum, detecting a displacement direction of the optical disc at the time of the pull-in, and moving the slider in the detected displacement direction for a distance equal to or almost equal to the eccentricity amount of the optical disc.

Abstract: A disc discriminating method for use in an optical disc drive includes the following steps. Firstly, an optical pickup head of the optical disc drive is controlled to move in a first direction when the optical pickup head is in a track-unlocked state. Then, a tracking error signal and a radio frequency signal are generated. According to the tracking error signal, a tracking error zero crossing signal is obtained. According to the radio frequency signal, a radio frequency zero crossing signal is obtained. According to a phase relation between the tracking error zero crossing signal and the radio frequency zero crossing signal, the disc is discriminated as an on-groove recording disc or an in-groove recording disc.

Abstract: An optical disk device includes a DPDTE signal generating section that detects misalignment between a light spot and a mark or a pit, an FE signal generating section, an optical crosstalk correcting section which corrects a signal output by the FE signal generating section using the DPDTE signal generating section, and a focus control section which controls an actuator so that a light beam converges on an information layer. The DPDTE signal generating section detects the misalignment on the basis of phase information obtained from signals received from predetermined light receiving areas. The optical crosstalk correcting section performs a correcting operation of removing a signal component from predetermined receiving areas of a detector which component is used for a DPDTE signal, the signal component being contained in the signals from the predetermined light receiving areas of the detector which signals are used by the FE signal generating section.

Abstract: A long seeking control method, for an optical information reproduction/recoding system having a lens and a sledge, includes: obtaining a sledge estimation velocity, a sledge estimation displacement, a sledge reference velocity and a first force applied to the sledge; determining to generate the sledge estimation velocity and the sledge estimation displacement in a first open loop control or in a first close loop control based on the sledge estimation velocity; determining to generate the a second force applied to the lens in a second open loop control or in a second close loop control based on the sledge estimation velocity; and pushing the sledge and the lens by the first force and the second force.

Abstract: A diffraction grating is constituted such that directions of diffraction are disposed asymmetrically with respect to the optical axis, by causing light subjected to aperture restriction to have a difference of one half wavelength in the optical path length by making use of the fact that the difference in the optical path length experienced by the light passing through a diffraction element varies depending on the wavelength. With this constitution of the diffraction grating, aperture restriction is applied to both the light focused on an optical disk and the light reflected from the optical disk, thereby achieving an optical pickup that is capable of recording/reproducing information on/from optical disks of different types by using a single objective lens. The optical pickup prevents unnecessary light from entering a photodetector and enables the production of diffraction elements at a low cost.

Abstract: A method for enhancing the optical initializing operation comprises: sending a radial error signal from an optical pick-up unit to a radial error signal calibration unit; sending the radial error signal from the optical pick-up unit to an offset adjuster; sending a calibrated radial error signal from the radial error signal calibration unit to the offset adjuster and a gain adjuster; sending a radial actuator (RA) signal from the radial error signal calibration unit to activate a radial actuator during an initialization or a period for calculating RE signal calibrating parameters.

Abstract: An optical disc apparatus of the present invention includes an optical head (103) including a lens disposed at a position shifted from a traverse axis in a tangential direction, a traverse motor (104) as a second moving unit that moves the optical head (103) in a direction traversing tracks of the optical disc (101), a number-of-tracks calculating part (123) that calculates, as the number of tracks to be sought, the number of tracks that the optical head will traverse when moving from a first address to a second address of the optical disc (101), a tracking-drive-signal-at-seek generating part (112) and a traverse-drive-signal-at-seek generating part (119) as seek controlling units that move a convergent point of an optical beam from the first address to the second address, and a number-of-tracks correcting part (124) that corrects the number of tracks to be sought according to a shift amount of the lens from the traverse axis.

Abstract: A conventional optical disk apparatus detects the amount of shift of an objective lens with a tracking error signal and an RF signal, and controls, when an optical pickup is moved, the shift amount for performing high-speed seek and high-speed access. The problem here is that this apparatus cannot be applied to an optical disk having an area where no RF signal is recorded, and requires higher costs. In view of this, an optical disk apparatus of the present invention has a shift signal detecting portion that detects a shift signal based on a push-pull signal generated during generation of a tracking error signal based on the reflected light resulting from a beam reflected from an optical disk, and a shift amount control portion that drives, when an optical pickup is moved, an objective lens actuator based on the shift signal detected by the shift signal detecting portion.

Abstract: An optical disk playback device includes a control means (an LSI 5 for system control) for performing a track search according to contents information, comparing a current track start point position at the time after performing the track search with a target track start point position, when the comparison result shows that they differ from each other, setting up a new target track start point position by performing a predetermined arithmetic operation, then performing a track search again, and, when a new current track start point position at the time after performing the track search again matches the set-up new target track start point position, starting a playback from the new current track start point position.

Abstract: A super-resolution material is formed in only a data pit, in a low temperature state of the super-resolution material, reflectivity of each of a pit portion and a space portion and an optical phase difference therebetween are set to be sufficiently small, in a high temperature state, and at least the optical phase difference between the pit and the space is set to be larger than the aforementioned value in an absolute value. Accordingly, by conducting irradiation with an appropriate read power by which substantially only one data track width can be heated to a high temperature state, a good push-pull signal can be obtained even with a track pitch being less than a diffraction limit.

Abstract: An optical disc device includes a control part for causing processing of determining a type of an optical disc to be executed. The processing caused by the control part to be executed for determining the optical disc includes: signal acquisition processing of acquiring a pull-in signal (sum signal of reflected signal) and an RF signal (reproduced signal) by moving an objective lens in either of a direction approaching the optical disc and a direction separating from the optical disc; and determination processing of deciding whether or not to correct the pull-in signal acquired in the signal acquisition processing and determining the type of the optical disc by using either of amplitude of the acquired pull-in signal and a correction value with which the amplitude of the acquired pull-in signal is corrected by using a predetermined value obtained from the acquired RF signal.

Abstract: An optical disc apparatus reliably executes a seek operation even if an optical disc is warped. Tilt adjustment values spanning from the inner circumference to the outer circumference of an optical disc are stored. When seeking from a start address to a destination address, a tilt adjustment value A at the start address and a tilt adjustment address C at the destination address are not directly used. A tilt adjustment value k·C (k<1) is used during a coarse seek operation until the neighborhood of the destination address and a tilt adjustment value C is used during a fine seek operation from the neighborhood of the destination address to the destination address.

Abstract: A portable data storage assembly, comprising a holographic data storage layer, and an optical tracking layer comprising addressing information for the holographic data storage layer, wherein that addressing information defines a first storage band comprising a first plurality of storage addresses and a second storage band comprising a second plurality of storage addresses, wherein said second plurality of storage addresses is greater than said first plurality of storage addresses.

Abstract: Disclosed herein are aspects of optical tape technology, tape manufacturing, and tape usage. Methods and systems of tape technology disclose optical tape media including: configurations, formulations, markings, and structure; optical tape manufacturing methods, systems, and apparatus methods and systems including: curing processes, coating methods, embossing, drums, testing, tracking alignment stamper strip; optical tape methods and systems including: pick up head adapted for the disclosed optical tape; and optical tape uses including optical storage media devices for multimedia applications.

Abstract: A tracking apparatus for an optical information reproduction apparatus includes the following: a photoelectric detector (1) in which a far-field pattern of a light spot converged on a recording medium is formed across a divided light-receiving cell; an arithmetic unit (2) for outputting at least a pair of arithmetic signals from the output of the photoelectric detector (1); a phase comparator (4) for detecting a phase difference between the output signals of the arithmetic unit (2); an absolute value detector (8) for detecting an absolute value of the output signal of the phase comparator (4); a level detector (9) for generating a signal that indicates whether or not a convergence position of the light spot is located off an information track by detecting a predetermined number of times or more the output signal of the absolute value detector (8) has become larger than a predetermined value; a sensitivity detector (10) for detecting and outputting the sensitivity of the level detector (9) by observing the out

Abstract: A detector is scanned across an optical storage medium having groove tracks and land tracks, each track having a wobble structure, to detect light reflected from the optical storage medium. A wobble signal and a tracking error signal are generated based on an output of the detector, and the wobble signal is sampled according to the tracking error signal. A determination about whether the detector is at the groove track or the land track is made based on the tracking error signal and a comparison of sampled values of the wobble signal.

Abstract: An optical disk medium includes a track groove thereon. On the optical disk medium, information is recorded along the track groove on a block unit basis. The block unit has a predetermined length. The block unit having the predetermined length includes a number of sub-blocks that are arranged along the groove. A sub-block mark is provided within each of the sub-blocks and used to identify the sub-block.

Abstract: An apparatus for recording and reproducing an information signal on and from an optical disc includes a memory. The information signal is written into the memory. The information signal is read out from the memory. An optical head generates a laser beam in response to the readout information signal, and applies the laser beam to the optical disc to record the readout information signal on the optical disc. A test signal is recorded on a position of the optical disc near a recording position thereof via the optical head during the writing of the information signal into the memory. The test signal is reproduced from the optical disc. The reproduced test signal is evaluated to generate an evaluation result. An intensity of the laser beam is optimized in response to the evaluation result.

Abstract: A track-jump control system and method are provided. The track-jump control system applied in an optical disc drive comprises a signal generator, a protection device, a velocity estimator, and a controller. The signal generator receives the signal from the PUH and generates a tracking signal and a position signal. The protection device receives the position signal and when the position signal represents the PUH pass a predetermined position of the optical disc, the protection device generates a protection signal. The velocity estimator estimates the velocity of the PUH according to the tracking signal, and then generates a velocity signal. The controller receives the velocity signal and the protection signal, protects the velocity signal according to the protection signal, and generates a control signal to control the track-jump according to the protected velocity signal.

Abstract: An optical disk writing method including determining a writing scheme for recording information on the optical disc based on received tracking error signals. The method also includes moving an optical pickup across tracks of the optical disc while the optical pickup emits a laser beam, counting a number of the tracking error signal, and determining a storage capacity of the optical disc based on the counted number of tracking error signals.

Abstract: An apparatus comprising a center error creation circuit and a center error offset injection circuit. The center error creation circuit may be configured to generate a center error signal in response to light from a main laser reflected from a surface of an optical disc. The center error offset injection circuit may be configured to (i) determine a value of the center error signal when a lens in a sled housing is at a mechanical center and (ii) generate an offset signal based upon the value. The center error offset injection circuit generally measures an average value of the center error signal over a predetermined amount of time when a lens suspension which holds the lens in place is in a mechanical equilibrium state.

Abstract: An optical disk device for recording or reproducing an optical disk has: an objective lens for irradiating a laser beam to the optical disk; an actuator for moving the objective lens in the radial direction of the optical disk; and a spindle motor for rotating the optical disk. After the laser beam irradiated to the optical disk passed through a PID portion of the optical disk, the actuator moves the objective lens in the radial direction of the optical disk at a timing corresponding to a rotational speed. Between signals to drive the actuator, an output time of a deceleration signal is set to a predetermined ratio of a time during which an acceleration signal is outputted. While the deceleration signal is outputted, a light spot passes through the PID portion.

Abstract: An optical disc apparatus includes a multilayer optical disc having a reproduction-only recording layer and a recording layer of the recordable area, on the disc, to record and reproduce the disc by the same wavelength laser light, so that a seek operation is performed rapidly, and a generation method tracking error signal (TE) is switched over by using a DPD method and push-pull method in response to a target layer to which a focus jump is applied, for a time period during which a tracking servo loop is opened in association with a focus jump.

Abstract: The liquid crystal element includes a pair of transparent substrates, a liquid crystal arranged between the substrates, a diffraction pattern including concentric diffraction electrodes formed on one substrate, and a phase shift pattern including concentric phase shift electrodes formed on the other substrate. The diffraction pattern includes a first region being of a constant range in a radial direction from a center and having a wide electrode interval, a second region being arranged on the outer side of the first region and having a narrow electrode interval, and a third region being arranged on the outer side of the second region and including a single diffraction electrode. An additional electrode facing the phase shift electrode is arranged in a gap between the diffraction electrodes in the first region.

Abstract: An optical pickup apparatus comprising: a first objective lens; and a second objective lens arranged with the first objective lens in a radial direction of an optical disc, the first objective lens being configured to focus laser light for reproduction, which is laser light for reproducing a signal recorded in a signal recording layer of the optical disc, onto the signal recording layer, the second objective lens being configured to focus laser light for recording, which is laser light for recording a signal, onto the signal recording layer.

Abstract: Before initiation of tracking control, an optical disk device performs an offset amount obtaining operation, in which a difference between a middle value of the amplitude of a tracking error signal and a predetermined reference value is obtained as an offset amount. After the initiation of the tracking control, the optical disk device initiates an attenuation operation, in which an offset amount attenuation section attenuates the offset amount obtained by the offset amount obtaining operation to obtain an attenuated offset amount, while initiating, with an initial value being 0, an estimation operation, in which an observer estimates the offset amount according to a tracking driving signal to obtain an estimated offset amount. The optical disk device corrects the tracking error signal by using the attenuated offset amount obtained by the attenuation operation and the estimated offset amount obtained by the estimation operation.

Abstract: In a track jumping scan control device wherein an optical beam is irradiated on an optical disc provided with a header region capable of a mark-recording operation with respect to both of land and groove tracks adjacent in a radial direction of the disc and comprising prepits, and a signal based on a reflected light resulting therefrom is used to make the optical beam jumping-scan with respect to a predetermined track, a full track jumping scan for making the optical beam track-jump between the land tracks or the groove tracks or a half track jumping scan for making the optical beam track-jump from the land track to the groove track or from the groove track to the land track is executed as the track jumping scan. Which of the two track jumping scans is executed is selected in accordance with a cycle at which the header region is set.

Abstract: A DSP of a DVD recorder includes: a gain setting portion determining appropriate values of a first gain ? and a second gain ? when playback of an optical disc is performed, recording the first gain ? and the second gain ? thus determined in a gain storing portion, and setting them in a main differential amplifier and a sub differential amplifier, respectively; and a correction performing portion reading, when recording on the optical disc is performed, the first gain ? and the second gain ? stored in the gain storing portion, correcting at least one of them, and setting them in the main differential amplifier and the sub differential amplifier, respectively.

Abstract: An optical disk apparatus is constructed for writing or reading information by irradiating a laser beam onto an optical disk while rotating the optical disk under a focus control of the laser beam relative to the rotated optical disk. In the optical disk apparatus, an irradiating section is operated to irradiate a laser beam onto the optical disk. A determining section determines a process pattern of the focus control by operating the irradiating section to irradiate the laser beam onto a predetermined area of the optical disk and by monitoring the laser beam reflected back from the predetermined area. A focusing section performs the focus control to regulate a spot diameter of the laser beam based on the determined process pattern during either of the writing or reading of information.

Abstract: For achieving pulling operation into tracking servo during seek operation at high-speed and with stability, in timing thereof, even on an optical disk forming lands and grooves on a recording surface thereof, in a seek control method, according to the present invention, for moving an optical spot onto an arbitrary track through movement of an optical pickup 110 into the radial direction on the optical disk forming the lands and the grooves, thereby forming a track on the recording surface thereof, in particular, in the seek operation, measurement is made on a period of a tracking error (TE) signal generated due to the movement in the radial direction, and a time point when the measured period of the tracking error signal exceeds a predetermined value is determined to be a starting point for pulling the optical spot of the optical pickup into the track, through the tracking servo, thereby pulling it selectively, into either one of the land and the groove building up the track.

Abstract: A method for reading/writing data of a disk drive that includes a spindle motor for rotating a disk and a head for reading/writing data from and to the disk. The method includes the steps of; (i) adjusting a position of the head for the first time to space apart the head from a center of the disk at a specific distance, wherein when the head is spaced apart from the center of the disk at the specific distance, the disk vibrates at the minimum magnitude during raising operation of the spindle motor from a low speed to a high speed; (ii) raising the spindle motor from the low speed to the high speed; and (iii) adjusting a position of the head for the second time to move the head to a desired track in the disk for reading/writing data in the desired track.

Abstract: A method for demodulating a tracking error signal comprising the steps of (A) demodulating the tracking error signal when starting motion, (B) demodulating the tracking error signal after motion has started, and (C) demodulating the tracking error signal before and after lens motion stops.

Abstract: A tracking offset is reduced. The effect of an SPP signal fluctuation is reduced by using a variable mixing ratio DPP method, and a residual tracking offset is minimized.